1. Field of the Invention
This invention relates to improvements in cleaning tools, and more particularly to improvements in tools for particular application in cleaning lpcvd furnace tubes, or the like.
2. Relevant Background
In the production of semiconductor products, low pressure chemical vapor deposition (lpcvd) apparatuses are used. Such lpcvd apparatuses typically have a processing tube, generally made of quartz, or similar material, that has a portion extending from the apparatus for connection to a vacuum line for evacuating the processing chamber. The processing tube has a relatively long portion, for instance, of about eight to twelve feet in length, having a diameter, for example of about eight to ten inches, within which the semiconductor wafers to be processed are located on a cantilevered beam.
The neck portion of the beam that extends from the processing chamber for connection to the vacuum line is of smaller diameter, for example, of about two to four inches. The neck portion may have a clamp receiving ridge or the like to removably secure a flange that attaches to a vacuum line to evacuate the interior of the tube and processing chamber into which it extends. The transition region between the larger and smaller diameter regions of the tube is usually smoothly curved, and the entire tube generally has a circular cross-sectional shape along its length to facilitate uniform gaseous flow therealong.
A major source of particles during the operation of such apparatuses, especially in processes involving silicon oxide or silicon oxynitride deposited using a tetra-ethyl-ortho-silicate (TEOS) source, or involving silicon nitride, is by-product deposits that build up inside the neck portion of the tube where it protrudes out of the furnace and attaches to the auxiliary plumbing connections. The by-products tend to deposit in this region because of the lower temperatures that exist in the regions of tube as it exits the processing apparatus. These deposits need to be periodically removed before they flake off and contaminate the actual deposition region inside the tube.
In the past, the removal of such deposits was done by disconnecting the auxiliary tube plumbing, then alternately scraping inside the neck and applying a vacuum to the outer end of the neck portion of the tube. The thoroughness of this procedure is highly operator dependent, and requires a great degree of care to perform. If not performed carefully and thoroughly, the process can, and often does, lead to higher particles inside the deposition zone near the tube neck due to recontamination inside the tube.